From 57be5bdad759b9dde8b0d0cc630782a1a4ac4b9f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 28 Nov 2014 13:40:20 -0500 Subject: ip: convert tcp_sendmsg() to iov_iter primitives patch is actually smaller than it seems to be - most of it is unindenting the inner loop body in tcp_sendmsg() itself... the bit in tcp_input.c is going to get reverted very soon - that's what memcpy_from_msg() will become, but not in this commit; let's keep it reasonably contained... There's one potentially subtle change here: in case of short copy from userland, mainline tcp_send_syn_data() discards the skb it has allocated and falls back to normal path, where we'll send as much as possible after rereading the same data again. This patch trims SYN+data skb instead - that way we don't need to copy from the same place twice. Signed-off-by: Al Viro --- net/ipv4/tcp.c | 233 ++++++++++++++++++++++++++------------------------------- 1 file changed, 106 insertions(+), 127 deletions(-) (limited to 'net/ipv4/tcp.c') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3075723..9d72a0f 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1067,11 +1067,10 @@ static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t size) { - const struct iovec *iov; struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *skb; - int iovlen, flags, err, copied = 0; - int mss_now = 0, size_goal, copied_syn = 0, offset = 0; + int flags, err, copied = 0; + int mss_now = 0, size_goal, copied_syn = 0; bool sg; long timeo; @@ -1084,7 +1083,6 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, goto out; else if (err) goto out_err; - offset = copied_syn; } timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); @@ -1118,8 +1116,6 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, mss_now = tcp_send_mss(sk, &size_goal, flags); /* Ok commence sending. */ - iovlen = msg->msg_iter.nr_segs; - iov = msg->msg_iter.iov; copied = 0; err = -EPIPE; @@ -1128,151 +1124,134 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, sg = !!(sk->sk_route_caps & NETIF_F_SG); - while (--iovlen >= 0) { - size_t seglen = iov->iov_len; - unsigned char __user *from = iov->iov_base; + while (iov_iter_count(&msg->msg_iter)) { + int copy = 0; + int max = size_goal; - iov++; - if (unlikely(offset > 0)) { /* Skip bytes copied in SYN */ - if (offset >= seglen) { - offset -= seglen; - continue; - } - seglen -= offset; - from += offset; - offset = 0; + skb = tcp_write_queue_tail(sk); + if (tcp_send_head(sk)) { + if (skb->ip_summed == CHECKSUM_NONE) + max = mss_now; + copy = max - skb->len; } - while (seglen > 0) { - int copy = 0; - int max = size_goal; - - skb = tcp_write_queue_tail(sk); - if (tcp_send_head(sk)) { - if (skb->ip_summed == CHECKSUM_NONE) - max = mss_now; - copy = max - skb->len; - } - - if (copy <= 0) { + if (copy <= 0) { new_segment: - /* Allocate new segment. If the interface is SG, - * allocate skb fitting to single page. - */ - if (!sk_stream_memory_free(sk)) - goto wait_for_sndbuf; + /* Allocate new segment. If the interface is SG, + * allocate skb fitting to single page. + */ + if (!sk_stream_memory_free(sk)) + goto wait_for_sndbuf; - skb = sk_stream_alloc_skb(sk, - select_size(sk, sg), - sk->sk_allocation); - if (!skb) - goto wait_for_memory; + skb = sk_stream_alloc_skb(sk, + select_size(sk, sg), + sk->sk_allocation); + if (!skb) + goto wait_for_memory; - /* - * Check whether we can use HW checksum. - */ - if (sk->sk_route_caps & NETIF_F_ALL_CSUM) - skb->ip_summed = CHECKSUM_PARTIAL; + /* + * Check whether we can use HW checksum. + */ + if (sk->sk_route_caps & NETIF_F_ALL_CSUM) + skb->ip_summed = CHECKSUM_PARTIAL; - skb_entail(sk, skb); - copy = size_goal; - max = size_goal; + skb_entail(sk, skb); + copy = size_goal; + max = size_goal; - /* All packets are restored as if they have - * already been sent. skb_mstamp isn't set to - * avoid wrong rtt estimation. - */ - if (tp->repair) - TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; - } + /* All packets are restored as if they have + * already been sent. skb_mstamp isn't set to + * avoid wrong rtt estimation. + */ + if (tp->repair) + TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED; + } - /* Try to append data to the end of skb. */ - if (copy > seglen) - copy = seglen; - - /* Where to copy to? */ - if (skb_availroom(skb) > 0) { - /* We have some space in skb head. Superb! */ - copy = min_t(int, copy, skb_availroom(skb)); - err = skb_add_data_nocache(sk, skb, from, copy); - if (err) - goto do_fault; - } else { - bool merge = true; - int i = skb_shinfo(skb)->nr_frags; - struct page_frag *pfrag = sk_page_frag(sk); - - if (!sk_page_frag_refill(sk, pfrag)) - goto wait_for_memory; - - if (!skb_can_coalesce(skb, i, pfrag->page, - pfrag->offset)) { - if (i == MAX_SKB_FRAGS || !sg) { - tcp_mark_push(tp, skb); - goto new_segment; - } - merge = false; - } + /* Try to append data to the end of skb. */ + if (copy > iov_iter_count(&msg->msg_iter)) + copy = iov_iter_count(&msg->msg_iter); + + /* Where to copy to? */ + if (skb_availroom(skb) > 0) { + /* We have some space in skb head. Superb! */ + copy = min_t(int, copy, skb_availroom(skb)); + err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy); + if (err) + goto do_fault; + } else { + bool merge = true; + int i = skb_shinfo(skb)->nr_frags; + struct page_frag *pfrag = sk_page_frag(sk); + + if (!sk_page_frag_refill(sk, pfrag)) + goto wait_for_memory; - copy = min_t(int, copy, pfrag->size - pfrag->offset); - - if (!sk_wmem_schedule(sk, copy)) - goto wait_for_memory; - - err = skb_copy_to_page_nocache(sk, from, skb, - pfrag->page, - pfrag->offset, - copy); - if (err) - goto do_error; - - /* Update the skb. */ - if (merge) { - skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); - } else { - skb_fill_page_desc(skb, i, pfrag->page, - pfrag->offset, copy); - get_page(pfrag->page); + if (!skb_can_coalesce(skb, i, pfrag->page, + pfrag->offset)) { + if (i == MAX_SKB_FRAGS || !sg) { + tcp_mark_push(tp, skb); + goto new_segment; } - pfrag->offset += copy; + merge = false; } - if (!copied) - TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; + copy = min_t(int, copy, pfrag->size - pfrag->offset); - tp->write_seq += copy; - TCP_SKB_CB(skb)->end_seq += copy; - tcp_skb_pcount_set(skb, 0); + if (!sk_wmem_schedule(sk, copy)) + goto wait_for_memory; - from += copy; - copied += copy; - if ((seglen -= copy) == 0 && iovlen == 0) { - tcp_tx_timestamp(sk, skb); - goto out; + err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb, + pfrag->page, + pfrag->offset, + copy); + if (err) + goto do_error; + + /* Update the skb. */ + if (merge) { + skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); + } else { + skb_fill_page_desc(skb, i, pfrag->page, + pfrag->offset, copy); + get_page(pfrag->page); } + pfrag->offset += copy; + } - if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) - continue; + if (!copied) + TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; + + tp->write_seq += copy; + TCP_SKB_CB(skb)->end_seq += copy; + tcp_skb_pcount_set(skb, 0); + + copied += copy; + if (!iov_iter_count(&msg->msg_iter)) { + tcp_tx_timestamp(sk, skb); + goto out; + } - if (forced_push(tp)) { - tcp_mark_push(tp, skb); - __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); - } else if (skb == tcp_send_head(sk)) - tcp_push_one(sk, mss_now); + if (skb->len < max || (flags & MSG_OOB) || unlikely(tp->repair)) continue; + if (forced_push(tp)) { + tcp_mark_push(tp, skb); + __tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH); + } else if (skb == tcp_send_head(sk)) + tcp_push_one(sk, mss_now); + continue; + wait_for_sndbuf: - set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); wait_for_memory: - if (copied) - tcp_push(sk, flags & ~MSG_MORE, mss_now, - TCP_NAGLE_PUSH, size_goal); + if (copied) + tcp_push(sk, flags & ~MSG_MORE, mss_now, + TCP_NAGLE_PUSH, size_goal); - if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) - goto do_error; + if ((err = sk_stream_wait_memory(sk, &timeo)) != 0) + goto do_error; - mss_now = tcp_send_mss(sk, &size_goal, flags); - } + mss_now = tcp_send_mss(sk, &size_goal, flags); } out: -- cgit v1.1